1. Field of the Invention
The present invention relates to a liquid ejection head for ejecting liquid and a process for producing the head. Specifically, the invention relates to an ink-jet recording head for conducting recording by ejecting ink onto a recording medium and relates to a process for producing the head.
2. Description of the Related Art
As an example of surface treatment of the face surface of an ink-jet head, U.S. Pat. No. 6,540,330 discloses a technique in which titanium oxide having photocatalytic activity is disposed on the face surface of an ink-jet head (hereinafter referred to as IJ head).
U.S. Pat. No. 6,540,330 relates to an IJ head having a passage configured by stacking two Si substrates. This IJ head is produced by forming a Ti compound (amorphous titania) on an orifice plate made of a Si substrate and then baking it at 400 to 500° C. The baking at a high temperature changes the Ti compound to anatase type titanium oxide. Therefore, the titanium oxide generated on the face surface is changed to be superhydrophilic by being irradiating with UV light, resulting in inhibition of adhesion of ink. As an additional effect, it is disclosed that the UV light decomposes the ink adherent. The IJ head disclosed in U.S. Pat. No. 6,540,330 has such a self-cleaning function, but the IJ head must be produced with an inorganic material because of the baking at a high temperature. Therefore, since the process and the material thereof are thus limited, it is concerned that it may be difficult to inexpensively produce the IJ head having high resolution.
US patent Publication No. 2007/0085877 discloses an IJ head having a hydrophobic layer that is composed of a hydrolyzable silane condensate including fluorine and a cation polymerizable functional group. This IJ head is produced by a photolithographic process, and it is supposed that the hydrophobic surface composed of a condensate of a silane compound is hard and is also excellent in blade durability. In addition, in US patent Publication No. 2007/0085877, it is disclosed that a partial hydrophobic region is provided by not imparting a hydrophobic characteristic to the region. Recently, various types of ink are used for ejection, and, thereby, further diversification of the face surface of the ejection orifice is required.